You probably bought a motorcycle and found a lot of numbers written on the tires but you have no idea what they mean. All these numbers represent some information regarding the motorcycle. Some represent measurements and ratings of the tire while others denote the expiry date of the motorcycle tires. Without knowledge, you may not know which number represents what.
Let's look at some of the most important numbers on the tire and what they stand for.
For example, if the tire on your bike reads, 180/45ZR-18 M/C, the following information goes on to explain what each letter or number represents;
80- The Width of the Tire
In this case, the first numbers are 1- 8- 0. Always, the second number represents the width of the motorcycle tire. Therefore, the number 80 is the represents the width of the tire. Width is the distance measured from one sidewall to the extreme point on the opposite sidewall. The width size differs from one touring motorcycle tire to the other.
45- Aspect ratio
The aspect ratio appears after the width in any of these three numbering systems; Metric, Low Profile Inch and Alpha. The aspect ratio is represented by the number that appears immediately after the forward slash (/). Aspect ratio is the cross-sectional profile that indicates the height to width ratio as a percentage. In this case, the aspect ratio45means that the tire's height is 45% of its width. It also varies from one tire to the other.
The Tire construction is always indicated after the speed rating using a letter. It can either be represented using B which means Belted orR which means Radial. This happens because; different tire companies have different ways of tire construction. For example, the tire construction from Harley motorcycle tires is totally different from any other tire.
Z- Speed rating
Speed rating means the maximum speed that the touring motorcycle tire can be used at while carrying a certain amount of load using a certain tire pressure. It is indicated by a letter (J-Z) that comes immediately after the aspect ratio. In some tires, it might be shown immediately after the width readings. The tire pressure and the maximum loads that can be supported are indicated on the tire sidewalls. A Z speed rating means that the maximum speed in KPH is anything above 240. Z rated tires do not have a speed limit which they can reach.
17- Rim Diameter
Next is the rim diameter. The rim diameter is the center distance from one tire sidewall to the opposite sidewall. It is the diameter of the circular open part formed by the tire where the rim fits. It is indicated immediately after the Tire construction. A hyphen comes first and the rim diameter follows. In this case, 17 is the rim diameter.
All these readings on the tire are useful during the purchase of new tires or rims. They help you to buy exactly similar tires to the previous ones that will be suitable for your touring motorcycle. Consider them the next time you replace your touring motorcycle tires. Be safe!
J Mary is an online automotive article writer specializing on Motorcycle tires and Exhausts. More information about her work on Harley Motorcycle Tires